关键词: 计算机辅助设计/计算机辅助制造, 硅橡胶, 微计算机断层扫描技术, 边缘及内部适合性

Abstract:

Objective To evaluate the effects of different scanning objects on the accuracy of computer aided design (CAD)/computer aided manufacture (CAM) Co-Cr metal porcelain crowns.Methods Fifteen Co-Cr metal porcelain crown specimens were fabricated by CAD/CAM technology. According to different scanning objects: prepared teeth, silicone rubber and stone die, they were divided into experimental B groups (group B1, B2, B3). Five specimens of traditional lost wax casting were used as control (group A). Marginal fits (AMD point and MG point) and internal fits (CA point, AW point, AOT point and OA point) were measured by the micro-CT. Statistical analysis was performed via one-way ANOVA and paired-t-test.Results The AMD point’ marginal fits of the experimental B groups were smaller than group A (P<0.05), there was no statistic difference in MG point’ marginal fits between the experimental B groups and group A. The experimental B groups had smaller internal fits than group A except OA point. The internal fits of group B1, 2 were smaller than the group A at AOT, AW and OA points (P<0.05), except group B3 (P>0.05). There was no statistic difference in CA point’ internal fits between the experimental B groups and group A (P>0.05).Conclusion The accuracy of silicone rubber is higher than the prepared tooth and stone die. Comparing to the traditional casting, the CAD/CAM has better marginal and internal fits.

Key words: computer aided design/computer aided manufacture, silicone rubber, Micro-CT, marginal and internal fit